This invention updates improvements on Romer U.S.. Pat. No. 4,679,737 for Grinding Sub-Sampling Mill and Method for preparations of Test Sample. This former mill applies to grains, soybeans, and pelleted feeds but does not apply to peanuts, tree nuts, silage, haylage or cottonseed. As mycotoxins as well as herbicides and pesticides can be found in these latter commodities in addition to the former, it is important to the food and agricultural industries that an improved grinding/subsampling mill be developed. No mill has been available that can even grind all of the above commodities including grains, soybeans, and pelleted feeds, much less simultaneously subsample the ground material. The previous mill also does not apply to large particles. Some pelleted feeds, including some dog foods, horse and cattle feeds, as well as pelleted corn gluten feed have pellets that are too large to fit into the patented Romer mill. Also commodities such as in-shell walnuts are too large for the patented Romer Mill Another new feature that has been found desirable involves the grind lever adjustments. The grind lever adjustment determines the distance between the stationary and rotating disks or burrs plates and thus the particle size. The grind lever on the Romer mill of U.S.. Pat. No. 4,679,737 can only be rotated about 1/2 a full revolution without the extra time and work of disengaging the grind lever. Also, the grind lever is located under the burr plates housing. This makes it somewhat awkward to rotate the grind lever but, more important, makes it necessary to place the grinder unit on its back in order to thoroughly clean the burrs and feed worm.
In the mill of this invention, the burr plates rotate vertically rather than horizontally and the grind lever is at the front of the unit. Also, the grind lever can be turned one full turn during which the particle size of ground corn, for example, can be changed from 1.0 mm to about 250 mm in diameter. This adjustment is necessary in order to set the proper grind size for different commodities as well to adjust for moisture and fat levels in each commodity. An added benefit of this ability to rapidly and drastically change the particle size is that a user who is testing corn for aflatoxin can easily "crack" the corn into four or five particles per kernel, perform the "blacklight test" which looks for bluish green fluorescent (BGF) dots on the corn particles. Such "glowers" are observable and characteristic of aflatoxin contaminated corn and provide a rapid simple "screening" test for aflatoxin contamination. If the BGF test is positive, the "cracked" corn can be reground to a fine particle size (by a simple adjustment with the grind lever) and a chemical test for aflatoxin can be performed.
The cleaning of the burrs and feed worm is also much easier with the mill of this invention. The cover plate directly faces the operator and after removing wing-nuts, the rotating burrs-feed worm can be removed as one piece. This whole cleaning process requires about one minute compared to the five minutes required for the patented mill.
In order to grind high fat items such as peanuts and tree nuts (almonds, walnuts, pistachios, brazil nuts, etc . . . ) it was necessary to modify the stationary burr-feed worm unit by putting a groove into the feed worm threads, an extra opening in the stationary burr plate, and removing some of the burrs on the rotating burr plate. High fat items can be pushed by the feed worm (which also has sharp cutting threads) with larger particles being recycled back through the opening in the top of the rotating burr plate and not ground to a fat slurry because of the removal of some of the burrs on the rotating burr plate.
The two different feed worm-burr plate units can be easily and rapidly exchanged. A different rotary burr plate-feed worm unit without the groove in the feed worm, opening in the top of the burr plate or removal of some burrs is used for corn and other low fat materials may be used as desired.
The new mill also applies to silage, hay, and cottonseed. Because the long feed worm at the base of the hopper constantly forces these materials into the burr plates whereas with the Patented Romer Mill, gravity is the force used to push the commodity into the small feed worm.
The "Dickens" mill of U.S. Pat. No. 3,830,436 is the only other mill found to be available for both grinding and subsampling agricultural commodities. However, the Dickens mill only applies to peanuts and does not apply to corn, silage, haylage or cottonseed and requires the use of a screen and concentric collection sector and does not employ the features of the instant invention. Also, I am not aware of the Dickens mill having been applied to tree nuts.
Because the burr sets on the newly invented mill are vertical, the 3 chute splitting system used with the patented mill does not apply (gravity would force most of the material to exit out of the lowest chute.) A new splitting device was designed that fulfills the same function, that is, from 10% to 80% of the ground material can be split from the stream of ground commodity in such a way that a representative subsample can be obtained.